Filter plate assembly for filter

ABSTRACT

A filter configured to separate the solid components and the liquid components from a slurry. The filter includes a plurality of filter plate assemblies that cooperate to define a plurality of filter chambers, each defining a perimeter having an open section when the filter plates are in a closed position relative to one another. Each filter plate assembly includes a closure configured to close the open section. Preferably, the closures are movable to an open position to permit a particulate cake to be removed from the filter chambers without separating the filter plates.

RELATED APPLICATIONS

Related applications are listed in an Application Data Sheet (ADS)accompanying this application. The entirety of each related applicationlisted on the ADS is expressly incorporated by reference herein.

BACKGROUND

1. Field of the Invention

The present invention is related generally to the field of separatingsolid and liquid components from a mixture. More specifically, thepresent invention is related to an improved filter plate assembly andrelated methods and filtering devices.

2. Description of the Related Art

Separating the liquid and solid components of a liquid-solid mixture, orslurry, is a necessary or desirable process in many industries. In manyfiltering applications, the slurry is a waste product and it isdesirable to separate the solid and liquid matter and dispose of themseparately. Often, the solid component may be a hazardous material andthe liquid component may be reused or recycled. In other applications,the liquid component may be the final product, such as in the juiceindustry, for example. In this application, the solid component isdesirably separated from the liquid to provide purity and clarity to thejuice.

One method for separating liquids and solids is known as surfacefiltering. In a surface filtering process, the liquid-solid mixture ispassed through a filter element under the influence of gravity or arelatively low pressure. The liquid component of the mixture passesthrough the filter element while the solid component is retainedprimarily on the surface of the filter element. However, with this typeof filtering process, once the surface of the filter element issubstantially covered with solid particulate matter, liquid is no longerable to pass through the filter element. The filter element must then becleaned or replaced. Thus, surface filter processes are useful only forfiltering slurries having a low concentration of solid matter.

Another method of filtering slurries having relatively highconcentrations of solid matter uses an apparatus known as a filterpress, which operates under a displacement filtering principle. A filterpress utilizes a series of filter plates placed adjacent to one another.A space is defined between each pair of the filter plates and each spaceis lined with filter media. Typically, each of the filter platesincludes a central aperture to permit all of the spaces between eachpair of plates communicate with one another. An inlet is provided tointroduce slurry into the interconnected spaces on an upstream side ofthe filter media. One or more outlets communicate with each space on adownstream side of the filter element.

Slurry is introduced through the inlet to fill all of the individualspaces between the filter plates. Once the spaces are filled, thedelivery pressure of the incoming slurry is increased such that theliquid component is displaced through the filter media and the solidparticulate matter is retained within the spaces upstream from thefilter media. The filtered liquid, or filtrate, moves to the outlet(s),where it is discharged. The filter cycle continues until each of thespaces is substantially filled with particulate matter. Thus, the filterpress utilizes substantially the entire volume of the spaces rather thanrelying on the surface area of the filter media, as is the case withsurface filtering methods.

The solid particulate “cake” remaining in each individual space afterthe filter cycle must be removed in preparation for a subsequent filtercycle. The removal of the particulate cake may be accomplished manuallyor, in some instances, automatically. In either case, the filter platesmust be separated from one another at least a distance equal to thethickness of the particulate cake to permit the particulate cake to bedischarged from the filter cavity. Because as many as a hundred or moreindividual plates may be used, the cleaning process is verytime-consuming and results in excessive down-time in which the filterpress is not utilized. In addition, the filter press must besubstantially longer than a length of the filter plates in order toprovide space to separate the plates. Furthermore, due to the provisionof multiple plates which need to be separated, fully automated filtercleaning systems employed with conventional filter presses are complexand often prohibitively expensive.

SUMMARY OF THE INVENTION

Preferred embodiments and methods permit automatic cake discharge for afilter press in a cost-efficient manner. The preferred embodiments andmethods permit particulate cake to be discharged from the filterchambers of a filter press, while the individual filter plates aremaintained in a compacted, or condensed, position. That is, preferably,the cake discharge is permitted with the individual filter platesseparated a distance that is less than a thickness of the particulatecake. More preferably, the individual filter plates are maintained incontact with one another during discharge of the particulate cake.

In one embodiment, a filter plate assembly includes a first filter plateand a second filter plate. The first filter plate has a first surfaceand the second filter plate has a second surface facing the firstsurface. The first and second filter plates are movable between an openposition and a closed position relative to one another. When the filterplates are in the closed position, an interior portion of the firstsurface is spaced from an interior portion of the second surface todefine therebetween a filter chamber having a perimeter. The filterplate assembly is capable of creating a seal between the first filterplate and the second filter plate, thereby defining a sealed section ofthe perimeter. The sealed section extends a length less than an entirelength of the perimeter such that the filter plate assembly also definesan open section of the perimeter. The open section is sized and shapedto permit particulate cake to be removed from the filter chamber. Thefilter plate assembly also has a closure configured to be movablebetween a first position closing the open section and a second positionnot closing the open section. The closure is further capable of sealingthe open section of the perimeter in the first position.

In another embodiment, a method of filtering includes forming a sealedfilter chamber with a filter plate assembly. The filter plate assemblyhas a first filter plate, a second filter plate, and a closure. Thefirst filter plate and the second filter plate are movable from an openposition to a closed position relative to one another to partially closethe filter chamber, thereby defining an open section of the filterchamber. The closure is configured to close the open section of thesealed filter chamber. A slurry is introduced into the filter chamber. Aliquid of the slurry is forced through a filter media lining at least aportion of the filter chamber until a particulate cake is formed withinthe filter chamber, which occupies a substantial portion of the filterchamber. The closure is removed while maintaining the first filter plateand the second filter plate in the closed position and the particulatecake is discharged through the open section of the filter chamber.

In yet another embodiment, a filter press has a frame including asupport surface. The filter press has a stationary head, a movable head,and a plurality of filter plates. The filter plates are supported by thesupport surface between the stationary head and the movable head. Theplurality of filter plates is movable relative to one another along thesupport surface between a separated position and a condensed position. Aforce generator is configured to apply a force to the movable head in adirection toward the stationary head to squeeze the plurality of filterplates between the movable head and the stationary head. The adjacentpairs of the filter plates are configured to form a partially sealedfilter chamber when the force generator applies a sufficient force tocreate a seal between the plurality of filter plates. A perimeter of thefilter chamber has an open section. A closure is configured to close theopen section. The closure is removable from the open section to permitparticulate to be removed from the filter chambers with the plurality offilter plates in the condensed position.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the present filterpress assembly are described with reference to drawings of the preferredembodiments. These embodiments are intended to illustrate, but not tolimit, the present invention. The drawings contain eighteen figures:

FIG. 1 is a perspective view of a filter press incorporating a pluralityof filter plate assemblies having certain features, aspects, andadvantages of the present invention.

FIG. 2 is a perspective view of an end portion of the filter press ofFIG. 1.

FIG. 3 is a cross section view of the filter press of FIG. 1 taken alongline 3-3 of FIG. 2, illustrating the filter cavities defined by thefilter plate assemblies. A scraper assembly is positioned within each ofthe filter cavities.

FIG. 3 a is an enlarged, partial view of the filter press of FIG. 3taken along line 3 a-3 a in FIG. 3. FIG. 3 a shows flow channels thatdeliver filtrate from the filter cavities to an outlet channel.

FIG. 4 is a cross-sectional view of modification of the filter pressembodiment of FIG. 3. The filter press of FIG. 4 introduces a slurry tothe individual filter cavities through a central feed channel, asopposed to the corner feed channels of the filter press of FIG. 3.

FIG. 5 a is a vertical cross-sectional view of one filter plate assemblyincluding a closure, which seals an open section of a perimeter of thefilter cavity. Preferably, a scraper assembly is carried by the closure.

FIG. 5 b is a vertical cross-sectional view of the filter plate assemblyof FIG. 5 a, with the closure and scraper assembly removed.

FIG. 6 is a cross-sectional view of the filter press of FIG. 1,illustrating the closures in a closed position.

FIG. 7 is a cross-sectional view of the filter press of FIG. 1,illustrating the closures in a partially open position.

FIG. 8 is a cross-sectional view of the filter press of FIG. 1,illustrating the closures in an open position.

FIG. 9 is an enlarged, partial view of the filter press of FIG. 7.

FIG. 10 is a transverse cross-sectional view of the filter press of FIG.6, with the closure in a closed position.

FIG. 11 is a transverse cross-sectional view of the filter press of FIG.7, with the closure in a partially open position.

FIG. 12 is a transverse cross-sectional view of the filter press of FIG.8, with the closure in an open position.

FIG. 13 is a perspective view of a filter plate assembly removed fromthe filter press and illustrating the closure and scraper assembly in apartially open position. The filter plate assembly includes a pair offilter plates separated by a frame.

FIG. 14 is a perspective view of one filter plate of the filter plateassembly of FIG. 13.

FIG. 15 is a perspective view of the frame of the filter plate assemblyof FIG. 13.

FIG. 16 is a perspective view of the closure and scraper assembly of thefilter plate assembly of FIG. 13.

FIG. 17 is a perspective view of a modification of the filter plateassembly of FIG. 13, wherein the scraper assemblies of two adjacentfilter plate assemblies are removed from opposing sides of the filterplate assemblies.

FIG. 18 a is a modification of the filter press of FIG. 1. In the filterpress of FIG. 18 a, a longitudinal axis of the filter plate assembly isoriented in a substantially vertical manner. Preferably, in most otherrespects the filter press of FIG. 18 a is substantially similar to thefilter press of FIG. 1.

FIG. 18 b shows the filter press of FIG. 18 a with the closures andscrapers in an open position. Adjacent scrapers and closures areconfigured to be opened from opposing sides of the filter plate assemblyin order to provide space for the particulate cake to be discharged.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A filter press is used to separate liquid and solid components from aliquid-solid mixture, such as a slurry or sludge. For example, thefilter press described herein is generally referred to by the referencenumeral 20 and can be used to filter a process fluid, industrial waste,municipal waste, or perform component separation in other settings. Thefilter press 20 may also be used in a variety of other industries.

During the filtering process, solids accumulate and form a particulatecake within filter chambers defined by the filter press 20. The filterpress 20 preferably includes a mechanism for rapidly discharging thecake from the filter chamber, without requiring the filter plates to beentirely separated from one another, as is described in greater detailbelow. For example, in one arrangement the cake can be removed from thefilter press by using a movable closure to permit access to the filterchamber. The methods and structures disclosed herein are described inthe context of a filter press, but are intended for application in anyof a wide variety filtering applications, as will be apparent to thoseof skill in the art in view of the disclosure herein. Further, thoseskilled in the art will recognize that many of the following disclosedembodiments, or portions thereof, may be modified and/or combined withone another to form further embodiments, and that no single feature isessential to the operation of the filter press. Thus, certain featuresand aspects of the filter press assemblies described below may also beused with a variety of other filtration devices.

FIG. 1 illustrates a filter press 20 that is configured to separatesolid and liquid components of a sludge or slurry. Preferably, thefilter press 20 includes an end stand 22, a collection of filter plates24, and a head stand 26. The collection of filter plates 24 arepositioned between the end stand 22 and the head stand 26. A pair ofrails 28 extend between the end stand 22 and the head stand 26 and,preferably, support the collection of filter plates 24. In theillustrated arrangement, each filter plate of the collection of filterplates 24 may be separated from the other filter plates, if desired, topermit removal or replacement of one or more of the individual filterplates or to provide access to the filter media. Alternatively, however,the filter plates may be connected together and may be configured toeither permit or inhibit relative movement between the filter plates, asdesired. In one arrangement, a portion or all of the collection offilter plates may be made up of a single, monolithic piece of material.

Generally, the filter press 20 passes a slurry through the filtercavities of the collection of filter plates 24, which utilize a filtermedia to retain the solid component of the slurry and permit the liquidcomponent, or filtrate, to exit the collection of filter plates 24. Thecollected solid component accumulates to form a cake of particulatematerial within each of the filter cavities. At the end of a filtercycle, the cake can be removed from the collection of filter plates 24so that a subsequent filter cycle can be performed.

The end stand 22 preferably includes a controller 30, a housing 32, anda force generator, such as a hydraulic force unit 34. The hydraulicforce unit 34 preferably is configured to apply a squeezing force to thecollection of filter plates 24 of a sufficient level to create a sealbetween each filter plate of the collection of filter plates 24. The endstand 22 also supports one end of the pair of rails 28 and preferablyhouses a portion of the hydraulic force unit 34, including at least aportion of a hydraulic cylinder 36 of the hydraulic force unit 34.

Preferably, the controller 30 is configured to permit a user to controloperating parameters of the filter press 20. For example, in onearrangement, the controller 30 is a numeric controller that permitsadjustment of the slurry feed parameters (such as feed pressure or flowrate of the slurry) and the force exerted by the hydraulic cylinder 36in squeezing the collection of filter plates 24. In the illustratedembodiment, the controller 30 is disposed on the top of the housing 32.However, the controller 30 can be provided in other suitable locationsto provide easy access to the controller 30.

In the illustrated embodiment, the housing 32 defines an inner chamber39 that generally houses the hydraulic force unit 34. The housing 32preferably includes a door 41 that provides easy access to the hydraulicforce unit 34. Those skilled in the art will recognize that there arevarious shapes and configurations of the housing 32 that would besuitable to house at least a portion of the hydraulic force unit 34. Insome arrangements, the housing 32 may not be necessary or desired.

The hydraulic unit 34 is configured to pressurize the hydraulic cylinder36 to apply a force to at least a portion of the collection of filterplates 24. In the illustrated embodiment, the hydraulic cylinder 36 hasa body 38 and a shaft, or piston rod 40 that extends outward from oneend of the body 38. The piston rod 40 can be moved inwardly andoutwardly of the body 38 to selectively apply, or release, a squeezingforce to the collection of filter plates 24.

Preferably, the exposed end of the piston rod 40 is coupled to amoveable head 42, which is supported by the pair of rails 28 on an endof the collection of filter plates 24 opposite the head stand 26. Thepiston rod 40 is configured to move the movable head 42 along the rails28 to selectively apply a squeezing force to the collection of filterplates 24 against a stationary head 44, which preferably is supported bythe head stand 26. Thus, the hydraulic cylinder 36 can move the movablehead 42 along a longitudinal axis of the filter press 20 toward or awayfrom the end stand 22 to selectively compress or release the collectionof filter plates 24.

Preferably, the collection of filter plates 24 includes at least onefilter plate assembly, generally referred to by the reference numeral46. More preferably, the collection of filter plates 24 includes aplurality of filter plate assemblies 46 that cooperate to filter solidsfrom a slurry. Desirably, each individual filter plate, with theexception of the end filter plates, forms a filter cavity with eachadjacent filter plate. Thus, each individual filter plate of the filterplate assemblies 46, with the exception of the end plates, form aportion of two separate filter plate assemblies 46, as is described ingreater detail below.

A slurry source 48 provides slurry to the filter press 20 and, morespecifically, to the collection of filter plates 24, as indicated by theslurry line 50 in FIG. 1. In the illustrated embodiment, the slurryprovided by the slurry source 48 passes through a supply passage 52disposed in a corner of the collection of filter plates 24. In analternative arrangement, the supply passage 52 may be disposed through acentral portion of the collection of filter plates 24, as describedbelow with reference to FIG. 4.

The supply passage 52 introduces slurry into each filter cavity of thecollection of filter plates 24. As slurry passes through the collectionof filter plates 24, an amount of slurry flows radially from the supplypassage 52 to fill the filter cavities within the filter plateassemblies 46, as illustrated by the arrows 53 in FIG. 1. The slurry isfiltered after it passes from the supply passage 52 by passing throughfilter media, which retains the solid component of the slurry andpermits the liquid component of the slurry, or filtrate, to be passedinto an opening 54 of one of a plurality of outlet passages 56. Thefiltrate flows through the outlet passage 56, which communicates witheach filter cavity downstream of the filter media and passes through thehead stand 26. The filtrate is discharged from an outlet 58 to becollected or used as desired.

In the illustrated embodiment, the filter plate assemblies 46 arevertically oriented plates that are movable, along a generallyhorizontal axis, between a closed, or condensed, position and aseparated position. However, in an alternative arrangement, the filterplate assemblies 46 may be stacked vertically, as described below withreference to FIG. 18, or in any other suitable orientation. The numberof filter plate assemblies 46 that form the collection of filter plates24 can vary greatly depending on the desired capacity of the filterpress 20. In general, a large number of filter plate assemblies 46 areprovided for a filter press 20 that is intended to filter a substantialamount of slurry during each filter cycle, while a smaller number offilter plate assemblies 46 may be sufficient for lower volume filteringapplications, or where the slurry to be filtered has a relatively lowconcentration of solids. Furthermore, the filter plate assemblies 46 mayalso vary in size to provide a desired capacity. Preferably, the filterplate assemblies 46 have height and width dimensions of about 18 inchesto about 58 inches or an area of up to about 2 square meters. In otherarrangements, larger filter plate assemblies 46 may be desirable.

Preferably, an upper surface of the pair of rails 28 support handles 47that are provided on opposing sides of each filter plate of thecollection of filter plates 24. The rails 28 are disposed on opposingsides of the collection of filter plates 24. Preferably, the handles 47slidably engage the upper surface of the rails 28 such that the filterplate assemblies 46 can be moved along the rails 28 to permit theindividual filter plates to be separated from one another.

The movable head 42 preferably includes skid brackets 60 that slidealong the upper surface of the rails 28 to permit the movable head 42 tomove along the rails 28. Thus, as described previously, the hydraulicforce unit 34 is capable of moving the moveable head 42 along the pairof rails 28 to selectively compress, or release, a portion or all of thecollection of filter plates 24. Alternatively, the movable head 42 maymove relative to the rails 28 on wheels or rollers or by any othersuitable arrangement. In one alternative arrangement, the pair of rails28 may be replaced by a single rail, which in some instances may belocated above the collection of filter plates 24. Such an arrangement isreferred to as an overhead filter press.

In FIGS. 1-3, the collection of filter plates 24 are illustrated in aclosed position. Although not illustrated, preferably, the individualplates of the collection of filter plates 24 can be moved into anuncompressed, or open position such that at least some of the plates 46are spaced from one another thereby exposing at least a portion of thefilter cavities of the collection of filter plates 24 or permittingremoval or replacement of one or more individual filter plates orprovide access to the filter media. However, preferably, the collectionof filter plates 24 are configured to permit particulate matter to beemptied from the filter chambers at the end of a filter cycle, withoutsignificantly separating the filter plates from one another, as isdescribed in greater detail below. Thus, alternative arrangements arepossible wherein the filter plates are not separable from one another orare assembled as an integral unit or formed as a monolithic structure.In one arrangement, the filter plates may be interconnected by adaisy-chain arrangement or a bellows-type arrangement, which permit thefilter plates to be separated from one another, preferably up to apredetermined distance.

With reference to FIG. 2, preferably, the filter press 20 includes afluid circulation system 62 configured to deliver slurry from the source48 to the collection of filter plates 24 and deliver filtrate from thecollection of filter plates 24 to the outlet 58. In the illustratedarrangement, the fluid system 62 includes the supply passage 52 alongwith a plurality of outlet passages 64, which communicate with theoutlet passages 56, described above with reference to FIG. 1.

Preferably, the supply passage 52 extends from a slurry pump 66 throughthe stationary head 44 and into the filter cavities of the collection offilter plates 24. The slurry pump 66 is configured to deliver slurryfrom the slurry source 48 to the supply passage 52. The outlet passages64 collect filtrate from the internal outlet passages 56 and deliver thefiltrate to the outlet 58, which is configured to discharge the filtrateto an appropriate location. In some applications, the filtrate may be adesired end product and may be collected. In other applications, thefiltrate may be disposed of through an appropriate mechanism, such as anindustrial waste removal system, for example.

With reference to FIG. 3, the collection of filter plates 24 preferablyincludes a plurality of filter plate assemblies 46. In the illustratedarrangement, the collection of filter plates 24 includes a tail filterplate 68 a, several intermediate filter plates 68, and a head filterplate 68 b. In general, all of the filter plates may be referred tousing the reference numeral 68, including the head and tail filterplates 68 a, 68 b. Those skilled in the art will recognize that thefilter plates 68, and resulting filter chambers, can be generallyrectangular, circular, or any other suitable shape when viewed along thelongitudinal axis of the collection of filter plates 24.

Preferably, a pair of filter plates 68 cooperate with one another toform a filter plate assembly 46, which defines a filter chamber 70.Preferably, both the head and tail filter plates 68 a, 68 b aresingle-sided. That is, each cooperates with only one other filter plate68 and the plates 68 a, 68 b are positioned at opposing ends of theintermediate filter plates 68. The intermediate filter plates 68preferably each cooperate with each adjacent filter plate 68. Thus, theintermediate filter plates 68 each cooperate with two other filterplates 68 and form a portion of two filter plate assemblies 46.

In the illustrated embodiment, a frame 72 is interposed between each ofthe filter plates 68. The frame 72 spaces the filter plates 68 apartfrom one another to define at least a portion of the thickness of thefilter chamber 70. In certain arrangements, the use of a frame 72permits the surfaces of the filter plates 68 facing the filter chamber70 to be planar such that the entire thickness of the filter chamber 70is determined by the thickness of the frame 72. Such an arrangement isadvantageous when a flat interior surface to the filter plates 68 isdesired, such as when a paper filter media is used, for example. Inother arrangements, the frame 72 may be omitted and the filter chambers70 may be defined by recessed portions of the cooperating filter plates68. Thus, although the illustrated filter plate assemblies 46 includeboth filter plates 68 and a frame 72, it is also possible to form thefilter chambers 70 without the frame 72 wherein the filter plates 68would provide the generally equivalent function of the frame 72, as willbe appreciated by one of skill in the art.

Each filter plate 68 preferably includes a corner opening 74, whichpermits fluid communication between the filter chambers 70 on opposingsides of the filter plate 68. Together, the corner openings 74 define acentral inlet passage 76 through the collection of filter plates 24 thatpermits fluid communication between all of the filter chambers 70. Thus,the inlet passage 76 permits slurry from the inlet passage 52 to bedelivered to each filter chamber 70. In other arrangements the inletpassage 76 can be disposed in other locations within the collection offilter plates 24. For example, the passage 76 may be formed within thecenter of the filter plates 68. Such an embodiment is described ingreater detail below with reference to FIG. 4.

With reference to FIGS. 3 and 3 a, preferably each filter plate 68includes a fluid passage 78 disposed on a downstream side of a filtermedia 80, which lines at least a portion of the filter chamber 70. Thepassage 78 is preferably disposed along a substantial portion of thefilter media 80 and is configured to permit the liquid component of theslurry to flow to the outlet passage 56. In the illustrated arrangement,the passage 78 is a recess region in the filter plate 68 in fluidcommunication with a channel 82 that, in turn, is connected to theoutlet passage 56. Liquid that passes through the filter media 80 isreceived in the passage 78 and then proceeds through the channel 82 andinto an outlet passage 56 due to a pressure differential between theinlet passage 52 and the outlet passages 56.

The passage 78 can have any shape or size suitable for receivingfiltrate through the filter media 80 and then delivering the filtrate tothe passage 56. For example, the filter plates may include protrusionson its surface to space the filter media 80 from the surface of thefilter plate 68 to create a space for fluid flow. Any other suitablearrangement can be used to achieve the desired passage 78.

Preferably, the filter media 80 is a permeable material that permitsliquid to pass therethrough, while preventing solids having a certainsize to pass therethrough. The filter media 80 can be, for example, afilter cloth, screen, paper, or any other suitable body for removingparticulate from the slurry. In the illustrated embodiment, the filtermedia 80 preferably defines substantially the entire vertical wall ofthe chamber 70. Further, the filter media 80 defines a substantialportion of the pair of vertical walls of the chambers 70.

With reference to FIGS. 3 through 5 b, preferably, a seal is formedbetween the filter plates 68 and interposed frames 72. With reference toFIG. 5 b, at least a portion of a perimeter of the filter chamber 70 isopen when the filter plates 68 and frames 72 are contacting one another,or are in a closed position. That is, the filter plates 68 and frames 72do not contact one another along the open section of the perimeter ofthe filter chamber 70. A closed section of the perimeter is definedwhere the filter plates 68 and frames 72 contact one another and form aseal therebetween. The seals inhibit, and preferably prevent, slurryfrom exiting the fluid chambers 70 by flowing between the filter plates68 and frames 72 at the sealed location when a sufficient squeezing, orclosing force is applied to the collection of filter plates 24.

With reference to FIG. 3 a, the frame 72 includes a surface 84 facing asurface 86 of the filter plate 68. When the frame 72 and the plate 68are in a closed position, the surface 86 is pressed against the surface84 to form a seal 88. Similarly, the intermediate filter plate 68includes a surface 90 facing a surface 92 of the frame 72. When theframe 72 and the filter plate 68 are in the closed position, at least aportion of the surface 90 is pressed against at least a portion of thesurface 92 to form a seal 94. In some arrangements, distinct sealingmembers may be used to assist in forming the seals 88, 94. For example,each of the seals 88, 94 can include a rubber member (e.g., a O-ring ora gasket) that is compressed between the filter plate 68 and a portionof the frame 72. However, those skilled in the art will recognize thatthere are other means that can be used for ensuring the integrity of thechamber 70.

As described above, preferably the filter plates 68 and the frame 72cooperate to define a perimeter 96 of the chamber 70. In the illustratedarrangement, the perimeter of the chamber generally refers to theportions of the filter chambers 70 facing the longitudinal axis of thecollection of filter plates 24. The seals 88, 94 provide a sealedsection of the perimeter 96 such that fluid cannot escape from thefilter chambers 70 of the collection of filter plates 24 as describedabove. Preferably, each of the filter chambers 70 are sealed in asimilar manner. The sealed section defined by the seals 88, 94preferably has a length that is less than the entire length of theperimeter 96 of the chamber 70 such that an open section 98 of theperimeter 96 is defined, as described above. As described above, in somearrangements, the frame 72 may be omitted and adjacent filter plates 68may contact one another.

In the illustrated embodiment, the frame 72 does not entirely surroundthe filter chamber 70 and defines a substantial portion of the opensection 98. The open section 98 communicates with an outlet 100, whichpermits particulate cake 102 to exit from between the filter plates 68through the open section 98.

With reference to FIGS. 5 a and 5 b, a closure 104 is configured toclose the open section of the perimeter 96 and create a seal with theframe 72 and/or the filter plates 68 to seal the filter chamber 70.Thus, with the closure 104 and the plurality of filter plates 24 in aclosed position, as illustrated in FIG. 5 a, the filter chamber 70 issealed and a filtering cycle may be carried out. The closure 104 maytake on many alternative shapes and sizes, depending on the shape andsize of the open section 98 of the filter chamber 70. For example, inthe illustrated arrangement, the closure 104 is in the shape of anelongated flange.

Once a filtering cycle has been completed, the closure 104 may be movedto an open position, as illustrated in FIG. 5 b, to permit access to thefilter chamber 70 through the open section 98. Preferably, the pluralityof filter plates 24 remain in a closed position while the closure 104 ismoved to the open position. In some instances, the hydraulic force unit34 may be reduced in pressure such that the collection of filter plates24 are no longer compressed sufficiently to seal the filter chambers 70.However, preferably, the collection of filter plates 24 are notseparated to any significant extent and, more preferably, are notseparated a distance greater than the width of the filter chamber 70. Insome arrangements, however, it may be desirable to separate the filterplates 68 by a distance greater than the width of the filter chamber 70.

With reference to FIG. 5 b, preferably the open section 98 is configuredand sized for convenient removal of the cake 102 (FIG. 4 a) from thechamber 70. In the illustrated arrangement, the width W1 (distance alonga longitudinal axis of the filter plate assembly 24) of the open section98 is approximately equal to the width W2 of the chamber 70. However, inalternative arrangements, the width W1 of the open section 98 may beless than or greater than the width W2 of the chamber 70. Thus, thereare various suitable shapes and sizes of the open section 98 suitable topermit cake to be removed from the filter press 20, preferably withoutsignificant separation of the filter plates 68.

In the illustrated arrangement, the closure 104 carries a scraperassembly 106. The scraper assembly 106 is configured to assist inremoval of the particulate cake 102 from the filter chamber 70.Preferably, the scraper assembly is carried by the closure 104 and,accordingly, moves through the filter chamber 70 along with movement ofthe closure 104. With reference to FIGS. 3 a and 4 b, the frame 72defines a groove 108 configured to receive at least a portion of thescraper assembly 106. When the closure 104 is moved from its closedposition at the end of a filter cycle, the scraper assembly 106preferably moves through the filter chamber 70 and removes at least aportion of the particulate cake 102, which is discharged through theopen section 98 of the perimeter 96 of the filter chamber 70.

The scraper assembly 106 preferably includes a surface that extends atleast partially across the width of the filter chamber 70 to assist inremoving the particulate cake 102. Preferably, the scraper assembly 106includes multiple surfaces that assist in moving the particulate cake102 toward the open section 98 of the perimeter 96 of the filter chamber70. In addition, the scraper assembly 106 may include additionalportions 110 that at least partially segment the filter chamber 70 toassist in breaking up the particulate cake 102 as the scraper assembly106 is removed from the filter chamber 70.

In operation of the filter press 20, the collection of filter plates 24are moved to the closed position to form the sealed filter chambers 70.The plates (e.g., the filter plates 68 and the frame 72) between themoveable head 42 and the stationary head 44 are squeezed together untilthe filter plates 68 contact the adjacent filter plate 68 or frame 72 toform the sealed filter chamber 70 for containing the pressurized slurry.

The closure 104 is moved to a closed position to block the opening 100and close the chamber 70, as shown in FIG. 6. When the closure 104 is inthe closed position, fluid within the chamber 70 is inhibited frompassing through the open section 98 and out of the opening 100.

During the filtering cycle, the slurry source 48 provides slurry thatpasses through the head stand 26 and into the collection of filterplates 24 in the direction indicated by the line 50 in FIG. 1. Thepassage 52 introduces slurry into the collection of filter plates 24along the corner inlet passage 76, as shown in FIG. 3. As slurry passesthrough the filter chamber(s) 70, pressure within the chamber 70 causesthe liquid component of the slurry to pass through the filter media 80and into the passage 78 and then into the passage 56 and out of thecollection of filter plates 24. The filter media 80 captures the solidcomponent of the slurry within the chamber 70. The solids within thechamber 70 accumulate to form a particulate cake 102.

At the end of the filter cycle, at least a portion of any liquidremaining within particulate cake can be remove by, optionally, applyingpressure to the cake during a squeeze or pressure cycle. With referenceto FIGS. 4 a and 4 b, to apply pressure to remove moisture within thecake 102, a pump (e.g., a diaphragm squeeze pump 111) is configured tosupply a pressurized fluid into a pair of passages 112 on either side ofthe cake 102. In the illustrated arrangement, each passage 112 isdefined by the surface of the filter plates 68 and a flexible membrane114, which is interposed between the filter plates 68 and the filtermedia 80, as will be appreciated by one of skill in the art. Thepressurized fluid within the passages 112 squeezes the cake between theopposing membranes 114.

When the membranes 114 apply pressure to the cake 102, liquid is forcedfrom the cake 102 through the media filter 80 and into the passage 78.Protrusions 116 defined by the membranes 114 provide a space betweenmembrane 114 and filter media 80 to form the passage 78 for passing theliquid component of the slurry into the outlet passage 56 (FIG. 3). Thesqueeze cycle preferably forms a dense cake 102 to facilitate removal ofthe cake by the scraper assembly 106. For example, the squeeze cyclepreferably reduces the force required to move the closure 104, andscraper assembly 106, from the closed position to the open position. Inone arrangement, each filter chamber 70 includes only one flexiblemembrane 114 that is preferably configured to squeeze the filter cake102 from only one side. Thus, the total number of cake squeezearrangements may be reduced thereby reducing manufacturing costs. Suchan arrangement is often referred to as a “mixed pack.”

If desired, a purge cycle can be utilized to further dry the cake 102.In one embodiment, a gas (e.g., air) can be passed into and out of thechamber 70. Moisture in the cake 102 is removed as the gas is blownthough and along the cake 102. The temperature of the gas may beambient, room temperature, or may be heated. Furthermore, a vacuum maybe applied to the filter chambers 70 to assist in drying the filter cake102. In another arrangement, the scraper assemblies 106, or any othersuitable component of the collection of filter plates 24 or filter press20, may be configured to vibrate to assist in breaking up theparticulate cake 102. A vibrator motor (not shown) may be used to impartvibrations to the scraper assemblies 106 or other component. Othermethods apparent to one of skill in the art to further dry and/or breakup the particulate cake 102 may be used alone or in any suitablecombination.

FIG. 4 illustrates a modification of the filter press 20 of FIG. 1. Thefilter press 20 of FIG. 4 preferably is substantially similar to thefilter press of FIG. 1 and, thus, like reference numerals are used toindicate like components. One difference between the filter press 20 ofFIG. 1 and the filter press 20 of FIG. 4 is that the filter press 20 ofFIG. 4 positions the inlet passage 52 generally in the center of thecollection of filter plates 24, as will be appreciated by one of skillin the art. In most other respects, the filter press 20 of FIG. 4 issubstantially similar to the filter press 20 of FIG. 1 and, thus, is notdescribed in further detail.

Returning to the filter press 20 of FIG. 1, with reference to FIGS.5-12, the filter press 20 preferably also includes a closure actuator,or closure rail 118, that is connected to the plurality of the elongatedmembers, or flanges 120, of the closures 104. The closure rail 118 maybe used to provide generally uniform movement of the closures 104relative to the collection of filter plates 24 and to move several orall of the closures 104 simultaneously. The closure 104 preferably ismoved vertically to move the closures 104 (and scraper assemblies 106,if provided) out of the filter plate assemblies 46. In an alternativearrangement, the closures 104 can be independently moved relative to theframes 72 depending on the application. In addition, the rail 118 can becoupled to a force generator, such as a hydraulic force unit, that isconfigured to move the closures 104 between an open and closed position.

With reference to FIG. 7, the closures 104 and scraper assemblies 106are illustrated in a partially opened position to permit access to thefilter chambers 70. The illustrated position can be achieved by movingthe closure rail 118 downwardly relative to the collection of filterplates 24.

With reference to FIG. 8, the closures 104 are positioned so that theupper end portion of the scraper assemblies 106 are located near thebottom portions of the filter chambers 70. Thus, preferably, in an openposition, a substantial portion of the scraper assemblies 106 extendfrom a lower end of the frames 72.

With reference to FIG. 13, a filter plate assembly 46 is shown separatefrom the filter press 20. In the illustrated arrangement, a pair offilter plates 68 are disposed on either side of the frame 72 to createthe filter plate assembly 46, as described above. The closure 104 isillustrated in a position partially extending from the opening 100 ofthe frame 72. Preferably, the opening 100 is configured to receive aportion of the closure 104. In one embodiment, the opening 100 has ends122, 124 that are configured to receive and engage the sides 126 of thescraper assembly 106. From the illustrated position, the closure 104 ismoved to the closed position by advancing the closure 104 into the frame72 in the direction of the arrow 128 a by sliding the sides 126 alongthe ends 122, 124. The closure 104 is advanced until the flange 120contacts the lower portion or surface 130 of the frame 72.

After the closure 104 reaches the closed position (shown in FIG. 6),such that the flange 120 forms a seal with the frame 72 and/or thefilter plates 68, slurry may pass into the chambers 70 and the slurry isinhibited from escaping through the opening 100. As the closure 104moves from the closed position in the direction of the arrow 128 b, atleast a portion of the cake disposed in the chamber 70 can be removedthrough the opening 100, preferably assisted by the scraper assembly106. The cake can be removed from the chamber 70 while the filter plateassembly 46 is in a closed position and, preferably, while maintainingthe seals between the filter plates 68 and the frame 72. As describedabove, in some arrangements, sealing pressure may be released from theplurality of filter plates 24, however, preferably the filter plates 68are not separated from one another by a distance that is greater than awidth of the filter chamber 70.

With reference to FIG. 15, the frame 72 can be configured to receive andhold the closure 104 and/or scraper assembly 106. In the illustratedembodiment, the frame 72 includes three sections creating a generallyU-shaped assembly. The frame 72 preferably includes a pair of generallyrectangular sections 132, 134 and a section 136 disposed between andconnecting one end of the sections 132, 134. In the illustratedarrangement, the sections 132, 134, and 136 cooperate to form threesides of the perimeter 96 of the filter chamber 70, as described abovewith reference to FIGS. 5 a and 5 b. However, the frame 72 can haveother configurations to define filter chambers 70 having other shapes.

Preferably, the frame 72 defines a groove, or slot 108, on each verticalside facing the filter chamber 70, which is configured to receive oneside of the scraper assembly 106. In addition, the section 136 defines aportion of the slot 108 such that the slot 108 is a generally U-shapedgroove or channel that receives at least a portion of the scraperassembly 106. Thus, one side of the scraper assembly 106 is slidablyengaged with one side of the slot 108, the other side of the scraperassembly 106 is slidably engaged with the other side of the slot 108,and the upper end of the scraper assembly 106 is engaged with the upperportion of the slot 108.

The sections 132, 134 of the frame 72 preferably also includes a handleor other protruding structure 137 that is configured to function as ahandle. The frame 132 also includes a pair of holes 138, 140 that definea portion of the inlet and outlet passages 52, 56, respectively.

With reference to FIGS. 9 and 16, the scraper assembly 106 preferablysupports a sprayer assembly 142, which is configured to spray a washfluid toward the filter media 80. Preferably, the sprayer assembly 142is disposed at the upper portion of the scraper assembly 106 and ismovable along with the scraper assembly 106 and closure 104 for cleaningthe filter media 80 of the filter chamber 70. In the illustratedembodiment, the sprayer assembly 142 includes a washer fluid source 144,a feed manifold 146, and at least one nozzle or sprayer 148.

The washer fluid source 144 (FIG. 9) is configured to provide a washfluid to the feed manifold 146. Wash fluid may travel from the fluidsource 144 to the feed manifold 146 through any suitable fluid passage.However, preferably, a portion of the fluid passage is defined withinthe scraper assembly 106. The washer fluid source 144 can deliver anyfluid suitable for being sprayed out of the sprayer assembly 142 andwashing the chambers 70. In the illustrated embodiment, the washer fluidsource 144 provides liquid in the form of water, with or withoutdetergents. In one embodiment, the washing liquid can be temperaturecontrolled for effective and rapid removal of solids from the filtermedia 80. For example, the fluid source 144 can deliver heated water tothe sprayers 148 at a high pressure so that the sprayer 148 can producehigh pressure spray 149 that rapidly cleans the filter media 80. Thoseskilled in the art will recognize that the fluid source 144 can provideany fluid (e.g., air, water, liquid chemicals) that can be used to cleanthe collection of filter plates 24.

The sprayer 148 is configured and adapted to direct washer spray againstat least a portion of the filter media 80. In the illustratedembodiment, the sprayer 148 delivers fluid from the washer fluid source144 to the filter media 80 along at least a portion of the chambers 70to dislodge and remove particulate disposed within the chamber 70. Forexample, at least one sprayer 148 can direct a spray of wash fluid 149towards at least a portion of the surface of the filter media 80.

Preferably, the sprayer assembly 142 has more than one and, in theillustrated arrangement, four sprayers 148, a pair of which are arrangedto spray one side of the filter chamber 70 while the other pair arearranged to spray the other side of the filter chamber 70. As theclosure 104 is moved relative to the frame 72, the sprayers 148preferably direct the washer fluid spray 149 towards the filter media 80to dislodge and remove particulate matter remaining after theparticulate cake has been discharged.

With reference to FIG. 16, the scraper assembly 106 preferably includesa pair of sides 126 that extend from the upper portion of a body 152 ofthe scraper assembly 106 to the lower portion of the body 152 and areconnected to at least one scraper member 110. The inner portion of thebody 152 defines at least a portion of the chamber 70, preferably atleast a portion of the perimeter 96 of the chamber 70.

The scraper member 110 includes opposing ends 154 a, 154 b and anelongated portion 156 therebetween. The ends 154 a, 154 b of the scrapermembers 110 are coupled to the sides 126 of the scraper assembly 106.Preferably, the scraper members 110 are disposed between the sprayerassembly 142 and the flange 120 and generally parallel to each other.When the closure 104 is in the closed position, the scraper members 110preferably extend substantially completely across the filter chamber 70,perpendicular to the longitudinal axis of the filter plate assembly 46.

In the illustrated embodiment, the elongated body 156 of each scrapermember 110 is generally horizontally oriented and is generallyrectangular in shape. However, the scraper member 110 can have othersuitable shapes for causing movement of the cake 102. For example, butwithout limitation, the scraper member 110 may have a generallycircular, elliptical, or polygonal cross section. Furthermore, as willbe appreciated, although the scraper members 110 are generallyhorizontally oriented in the illustrated embodiment, in otherarrangements the scraper members 110 may have other orientations. Forexample, the scraper members 110 may be vertically oriented, such aswhen the scraper assembly 106 is configured for movement in a horizontaldirection. Thus, in some preferred arrangements, the scraper members 110are oriented substantially normal to the direction of movement of thescraper assembly 106.

The scraper assembly 106 can have any suitable number of scraper members110 configured to remove solids from the filter chamber 70. In oneembodiment, the scraper assembly 104 has one scraper member 110. Inanother embodiment, the scraper assembly 104 has a plurality of scrapermembers 110. In the illustrated embodiment, the scraper assembly 104 hasfour scraper members 110. Each of the scraper members 110 can have ashape similar to the other scraper members 110. However, alternatively,the scraper members 110 can have shapes different than the other scrapermembers 110. Furthermore, the scraper members 110 can be disposed indifferent positions along the sides 126. In the illustrated embodiment,the scraper members 110 are generally evenly spaced between an upperportion 158 of the body 152 and a lower portion 160 of the body 152.However, the scraper members 110 can be unevenly spaced between theportions 158, 160 for the desired scraping and thermal characteristics,as described herein.

Preferably, the scraper members 110 are configured to engage and segmentat least a portion of particulate cake that forms in the filter chambers70 of the collection of filter plates 24. As illustrated in FIG. 5 a,for example, the cake 102 surrounds at least a portion of the scrapermembers 110 after an amount of solid component of the slurry has beencaptured by the collection of filter plates 24. When the closure 104 ismoved relative the filter plates, outer surfaces 162 of the scrapermembers 110 engage the particulate cake 102 to break it up and urge thecake 102 downwardly through the opening 100 and out of the collection offilter plates 24. Thus, preferably, the scraper members 110 havesufficient structural characteristics to assist in breaking apart theparticulate cake 102. In the illustrated arrangement of FIGS. 5-16, thescraper members 110 extend substantially entirely across the filterchamber 70. In some arrangements, the scraper members 110 may evencontact the filter media 80.

In one arrangement, the scraper member 110 is configured to circulate aheating fluid, from a heating fluid source (not shown), in thermalcommunication with the particulate cake within the filter chambers 70 toassist in drying the particulate cake. As illustrated in FIG. 16,preferably at least a portion of the scraper members 110 define aninternal passage or channel 164 for carrying a heating fluid (such assteam or hydraulic fluid, for example) to thermally communicate with thecake 102 within the chambers 70. The channel 164 has a longitudinal axisthat is generally aligned with the longitudinal axis of the scrapermember 110 and, preferably, the channels 164 of the individual scrapermembers 110 communicate with one another to circulate the heating fluidthroughout the filter chamber 70 to drying, or reduction of moisture, ofthe particulate cake 102.

With reference to FIG. 16, preferably, the scraper assembly 106 carriesat least one stay boss 166. Alternatively, if no scraper assembly 106 isprovided, the stay boss can be carried by the closure 104. As will beappreciated by one of skill in the art, the stay boss 166 is configuredto support the filter plates 68 to resist deformation of the filterplates 68 along the longitudinal axis of the collection of filter plates24 during a filter cycle. In the illustrated embodiment, a single stayboss 166 is provided which is a generally solid plate connected to apair of scraper members 110 near the central region of the scraperassembly 106. When the scraper assembly 106 is within the chamber 70,the stay boss 166 is interposed between the walls of the chamber 70 andis configured to prevent substantial displacement of at least a portionof the walls of the chamber 70. Furthermore, the stay boss 166 canprovide structural support to the scraper members 110. Although notillustrated, a plurality of stay bosses 166 can be coupled to theclosure 104.

The stay boss 166 may take on various shapes depending on desiredstructural characteristics and configuration of the chamber 70. Forexample, the stay boss 166 may be generally square, rectangular,circular or elliptical and can be attached to one or more members, suchas the scraper members 110. The stay boss 166 can also define a surfacethat is configured to dislodge cake formed within the chamber 70 as thescraper assembly is moved between the closed and open position.

Preferably, the stay boss 166 extends substantially across the axialwidth of the filter chamber 70. That is, the dimension of the filterchamber 70 along the longitudinal axis of the filter press 20. Morepreferably, the stay boss 166 contacts the filter media of each filterplate 68 when the filter plates are in a closed position. Preferably, astay boss 166 is provided if the filter chamber 70 has a height or widthdimension (in a plane generally perpendicular to the longitudinal axisof the filter press 20) of more than about 20 inches. However, one ormore stay bosses may be provided for filter chambers 70 having adimension less than 20 inches, if desired. Those skilled in the art candetermine the suitable size, configuration, and orientation of the stayboss 166 depending on the desired interaction between the boss 166 andthe filter plates 68.

Although not illustrated, the closure 104 and the scraper assembly 106can be separate components that can be independently operated. In oneembodiment, for example, the closure 104 preferably includes the flange120 for closing the opening 100. The scraper assembly 106, if provided,is preferably disposed within the filter chamber 70 of the collection offilter plates 24. The closure 104 may be removed after the filteringcycle so that the scraper assembly 106 can be employed to remove cake102. In some arrangements, a scraper assembly 106 may not be necessaryor desired and, thus, may not be provided.

With reference to FIGS. 14 and 15, preferably the frames 72 and thefilter plates 68 are keyed together to reduce or eliminate relativemovement between the particulate filter plates 68 and the frame 72 whenslurry is pressurized within the filter chambers 70. Preferably, theframe 72 is keyed to at least one filter plate 68 to inhibit expansionof the frame 72, in a radial direction, in response to fluid pressurewithin the chamber 70. In the illustrated embodiment of FIGS. 14 and 15,the frame 72 has a key recess 168 that is configured to receive aprotrusion or key 170 on the plate 68. Preferably, the frame 72 has apair of key recesses 168 on each of the section 132, 134 that areadapted to mate with a pair of corresponding keys 170 of the plates 68.Additionally, both sides of the frame 72 preferably have key recesses168 such that plates 68 on both sides of the frame 72 are keyed to theframe 72.

Although not illustrated, the key recess 168 can be a hole, or otherstructure that is configured to receive a structure on the plate 68.Alternatively, the frame 72 can have a key or protrusion that isconfigured to be received within a key recess of the plate 68. Inanother embodiment, the frame 72 and the plate 68 can have ridges orgrooves that are configured to engage each other to prevent relativemovement between them. In addition, a separate key member may beprovided to engage recesses in both the plates 68 and frame 72.Furthermore, other methods for inhibiting radial expansion of the frame72 may also be utilized, such as internal or external bracing within theframe 72, for example, but without limitation. In one arrangement, theside rails 28 may be configured to contact the sides of the frame 72 toinhibit radial expansion. In such an arrangement, the rails 28 may besized to contact a substantial portion of the length of the frame 72 oreven the entire length of the frame 72.

With respect to FIG. 10, the closure 104 is illustrated in the closedposition. Preferably, as described above, the closure 104 forms a sealwith the frame 72 and/or plates 68 to prevent fluid from escaping fromthe filter chamber 70 during operation. Preferably, the seals formedbetween the closure 104 and the frame 72 and/or plates 68 substantiallyprevent slurry from passing from the filter chambers 70.

As described above, the particulate cake 102 may be heated to assist indrying the cake 102. Heated fluid is preferably passed through thechannels 164 of the scraper assembly 106 so that heat from the fluidwithin the channel 164 is conducted to the cake 102, and thus heats thecake. Preferably, the channel 164 is sized such that a sufficient amountof fluid can be passed through the scraper member 110 to effectivelywarm the cake within the collection of filter plates 24. The heating ofthe cake 102 can be used in combination with the squeeze cycle to ensurethat the cake 102 is sufficiently dry for convenient removal andcollection.

As described above, a purge cycle may be utilized to further dry thecake 102. In one embodiment, a gas (e.g., air) is passed into and out ofthe chamber 70. Moisture in the cake 102 is removed as the gas is blownthrough and along the cake 102.

The closure 104 can be moved from the closed position to an openposition to move the scraper assembly 106 and assist in removing theparticulate cake 102 from the filter chamber 70. The closure 104 can bemoved from the closed position by downwardly moving the closure 104relative to the adjacent filter plates 68 and out of the opening 100.This movement urges the cake within the chambers 70 out of the opening100. The speed that the closure 104 is moved from the closed position tothe open position may be determined by the characteristics of the cake102.

Preferably, the filter plates 68 remain in, or close to, a closedposition contacting the frame 72 as the closure 104 is moved to the openposition. Thus, the collection of filter plates 24 can be held betweenthe heads 42, 44 such that the filter plates 68 (and frames 72) are in arelatively compressed position relative to one another while the closure104 is moved from the closed position to the open position. Further,several closures 104 can be moved simultaneously from the closedposition to the open position by moving the rail 118. Thus, the chambers70 can be emptied of solids without separating the filter plates 68 andthe frames 72 from one another.

Alternatively, the piston rod 40 can be retracted to reduce thecompressive force on the collection of filter plates 24. After thereduction of pressure on the collection of filter plates 24, the closure104 may be moved from the closed position to the open position todischarge the cake. The reduced pressure can facilitate convenientremoval of the closure 104 and removal of the cake 102. In anotherarrangement, the filter plates 68 and frames 72 may be separated a smalldistance to further reduce the force necessary to discharge theparticulate cake 102. However, preferably, the plates 68 are notseparated a distance greater than the width W1 of the filter chamber 70or particulate cake 102.

While slurry is being filtered within the collection of filter plates 24during the filtering cycle, the closure 104 preferably is in the closedposition and the sprayer assembly 142 is off so that substantially nofluid is sprayed from the sprayers 148. At the end of the filter cycle,the closure 104 is moved from the closed position by moving the closure104 relative to the adjacent filter plates 68 and out of the opening100. This movement assists the cake 102 within the chambers 70 in beingdischarged from the opening 100, as described above. Preferably, theclosures 104 are then moved to a closed position and the sprayers 148are activated to direct a spray of wash fluid toward the filter media80, while the closure 104 is pulled out of the opening 100 to washsubstantially the entire length of the filter media 80 from the top tothe bottom of the filter chamber 70.

FIG. 17 illustrates a modification of the filter plate assembly 46 ofFIG. 13. The filter plate assembly 46 of FIG. 17 is substantiallysimilar to the filter plate assembly 46 of FIG. 13 and, therefore, likereference numerals are used to denote like components. FIG. 17illustrates a pair of individual filter plate assemblies 46, includingtwo frames 72 and three filter plates 68. As described above, the firstfilter plate assembly 46 includes the forward-most plate 68, theforward-most frame 72 and the intermediate plate 68. The second filterplate assembly includes the rearward-most plate 68, the rearward-mostframe 72 and the intermediate plate 68. Thus, the intermediate plate 68forms a portion of each illustrated filter plate assembly 46.Furthermore, the forward-most and rearward-most plates 68 may form aportion of filter plate assemblies (not shown) that are adjacent theillustrated filter plate assemblies 46.

The filter plate assemblies 46 of FIG. 17 are substantially similar toany of the filter plate assemblies 46 described in relation to FIGS.1-16. However, in the assemblies 46 of FIG. 17, the closures 104 andscraper assemblies 106 of the forward-most filter plate assembly 46 andthe rearward-most filter plate assembly 46 open from different sides ofthe filter plate assemblies 46. That is, the closures 104 and scraperassemblies 106 extend from the filter plate assemblies 46 in differentradial directions from one another relative to a longitudinal axis A_(L)of the assemblies 46. Preferably, the closures 104 and scraperassemblies 106 extend from opposing sides of the filter plate assemblies46 and, more preferably, from opposing vertical sides of the filterplate assemblies 46. The closures 104 and scraper assemblies 106 may bemoved by separate closure mechanisms or by the same closure mechanism.Such an arrangement provides additional space between adjacent closures104 and scraper assemblies 106 to permit the particulate cake to beeasily discharged without interference from the particulate cake ofadjacent filter cavities.

With reference to FIGS. 18 a and 18 b, a modification of the filterpress 20 of FIG. 1 is illustrated. Preferably, the filter press 20 ofFIGS. 18 a and 18 b is substantially similar to the filter press 20 ofFIG. 1 and, therefore, like reference numerals are used to denote likecomponents. However, in the filter press 20 of FIGS. 18 a and 18 b, thelongitudinal axis of the collection of filter plates 24 is oriented in agenerally vertical direction. Accordingly, with such an arrangement,less floor space is used compared with the filter press 20 of FIG. 1.

The filter press 20 preferably is supported by a frame assembly 150,which accommodates the hydraulic cylinder 34. The hydraulic cylinder 34is configured to selectively apply or remove a squeezing force to thecollection of filter plates 24. The hydraulic cylinder 34 may also beconfigured to retract to permit the individual filter plates 68 (andframes 70, if provided) to separate from one another. Preferably, alinking structure 152, such as a cable or chain, for example,interconnects the adjacent filter plates 68 (or a frame 70 and a filterplate 68) such that when the hydraulic cylinder 34 is withdrawn, thefilter plates 68 (and frames 70, if provided) are held in a spacedrelationship by the linking structures.

Preferably, the filter press 20 of FIGS. 18 a and 18 b include closures104 and scraper assemblies 106 which, desirably, are similar to thosedescribed with reference to the filter press 20 of FIG. 1. In the filterpress 20 of FIGS. 18 a and 18 b, adjacent closures 104 and scraperassemblies 106 are removed from different sides, and preferably opposingsides, of the collection of filter plates 24 to permit the particulatecake to be discharged without interference from the particulate cake ofadjacent filter cavities. Preferably, the filter press 20 comprises adrive mechanism 154 that is configured to move the closure rail 118 andclosures 104. Desirably, the drive mechanism 154 comprises a linkagearrangement configured to convert linear movement in a directiongenerally parallel to the longitudinal axis of the filter press 20 intolinear movement of the closure rail 118 in a direction generallyperpendicular to the longitudinal axis of the filter press 20. However,other suitable arrangements to move the closure rail 118 and/or closures104 may also be used.

Although the present invention has been described in terms of a certainembodiment, other embodiments apparent to those of ordinary skill in theart also are within the scope of this invention. Thus, various changesand modifications may be made without departing from the spirit andscope of the invention. For instance, various components may berepositioned as desired. Moreover, not all of the features, aspects andadvantages are necessarily required to practice the present invention.Accordingly, the scope of the present invention is intended to bedefined only by the claims that follow.

What is claimed is:
 1. A filter plate assembly, comprising: a firstfilter plate having a first surface; a second filter plate having asecond surface facing said first surface, said first and second filterplates movable between an open position and a closed position relativeone another, wherein in said closed position an interior portion of saidfirst surface is spaced from an interior portion of said second surfaceto define therebetween a filter chamber having a perimeter; wherein saidfilter plate assembly is capable of creating a seal between said firstfilter plate and said second filter plate, thereby defining a sealedsection of said perimeter, said sealed section extending a length lessthan an entire length of said perimeter such that said filter plateassembly also defines an open section of said perimeter, said opensection being sized and shaped to occupy a substantial entirety of aside of said perimeter such that an entirety of the particulate cake canbe removed from said filter chamber; and a closure configured to bemovable in a linear direction between a first position closing said opensection and a second position not closing said open section, saidclosure further being capable of sealing said open section of saidperimeter in said first position.
 2. The filter plate assembly of claim1, additionally comprising a frame between said first filter plate andsaid second filter plate, said frame defining at least a portion of saidopen section of said perimeter.
 3. The filter plate assembly of claim 2,wherein said perimeter has four sides, said frame bounding three sidesof said perimeter.
 4. The filter plate assembly of claim 2, wherein saidframe is keyed to at least one of said first filter plate and saidsecond filter plate to inhibit expansion of said frame in response topressure within said filter chamber.
 5. The filter plate assembly ofclaim 1, wherein said closure carries a scraper, said scraper having ascraper surface extending between said first surface and said secondsurface and configured to urge particulate cake within said filterchamber toward said open section when said closure is moved toward saidsecond position.
 6. The filter plate assembly of claim 5, wherein saidscraper surface extends substantially completely across said filterchamber from said first surface to said second surface.
 7. The filterplate assembly of claim 5, wherein said scraper comprises multiplescraper surfaces spaced from one another which segment particulate cakewithin said filter chamber.
 8. The filter plate assembly of claim 5,wherein said scraper comprises an internal fluid passage configured tobring a fluid into thermal communication with particulate cake withinsaid filter chamber.
 9. The filter plate assembly of claim 5, whereinsaid closure carries at least one spray nozzle, said spray nozzleconnected to a wash fluid source and being configured to direct a sprayof wash fluid toward at least one of said first surface and said secondsurface.
 10. The filter plate assembly of claim 1, wherein said closurecomprises a portion extending into said filter chamber, said portionsupporting at least one stay boss extending substantially across saidfilter chamber from said first surface to said second surface.
 11. Thefilter plate assembly of claim 1, wherein said perimeter includes anouter perimeter and a length of said outer perimeter equals a length ofsaid sealed section plus a length of said open section.
 12. A method offiltering, comprising: forming a sealed filter chamber with a filterplate assembly comprising a first filter plate, a second filter plate,and a closure, said first filter plate and said second filter platebeing movable from an open position to a closed position relative to oneanother and a closing force applied to said first and second filterplates to partially close said filter chamber, thereby defining an opensection of said filter chamber, said closure being configured to closesaid open section of said sealed filter chamber; introducing a slurryinto said filter chamber; forcing a liquid component of said slurrythrough a filter media lining a least a portion of said filter chamberuntil a particulate cake is formed within said filter chamber, saidparticulate cake occupying a substantial portion of said filter chamber;reducing said closing force and maintaining said first filter plate andsaid second filter plate in said closed position; removing said closurein a linear direction; and discharging said particulate cake throughsaid open section of said filter chamber.
 13. The method of claim 12,additionally comprising positioning a frame between said first filterplate and said second filter plate, said frame at least partiallydefining said open section.
 14. The method of claim 13, additionallycomprising keying said frame to at least one of said first filter plateand said second filter plate to inhibit expansion of said frame inresponse to pressure within said filter chamber.
 15. The method of claim12, wherein said discharging of said particulate cake is facilitated bya scraper, which is movable through said filter chamber along withmovement of said closure away from said open section.
 16. The method ofclaim 12, additionally comprising providing a scraper within said filterchamber during a filter cycle, said scraper configured to segment saidparticulate cake.
 17. The method of claim 12, additionally comprisingproviding a scraper within said filter chamber during a filter cycle,drying said particulate cake within said filter chamber by circulating aheated fluid within an internal fluid passage of said scraper.
 18. Themethod of claim 12, additionally comprising directing a spray of washfluid toward said filter media after said discharging of saidparticulate cake through said open section of said filter chamber andwhile maintaining said first filter plate and said second filter platein said closed position.
 19. The method of claim 12, additionallycomprising resisting deformation of said first filter plate and saidsecond filter plate in response to pressure external of said filterchamber by positioning at least one stay boss within said filter chamberduring a filter cycle, said stay boss being carried by said closure.